1. Field of the Disclosure
The present disclosure relates to an optical compensator for enhancing the viewing angle of a liquid crystal display.
2. Description of the Related Art
Recently, various liquid crystal display (LCD) modes and compensation films have been proposed to enhance the viewing angle of LCDs. Vertically-aligned (VA) LCD is a typical example of LCDs with wide viewing angle. Vertically-aligned (VA) LCD is a mode using a negative liquid crystal material and vertical alignment film. When no voltage is applied, liquid crystal molecules are aligned in a vertical direction and black display appears. When a predetermined voltage is applied, the liquid crystal molecules are aligned in a horizontal direction and white display appears. Comparing to the twisted nematic (TN) LCD, the vertically-aligned (VA) LCD provides higher contrast, higher response speed, and excellent viewing angle characteristics. However, the VA LCD still has problems of color shift or narrow viewing angle due to a dark-state light leakage at large viewing angles which reduces the contrast. Typically, these problems can be reduced by introducing compensation films.
However, the performance of conventional compensation films are not acceptable since all of them are optimized for a single wavelength of light while not considering other wavelengths of the electromagnetic spectrum which are visible by human eyes.